This invention relates to a rotary type heat treatment which heat-treats a material, and to a temperature control method for the device. In the invention, the term "heat treatment" is intended to mean the drying or sintering treatment of a material. Hence, the invention is useful for continuously and stably drying or sintering a material.
Heretofore, in order to continuously dry or sinter a material containing moisture, a variety of drying devices or sintering devices such as "a dryer" or "a calciner" are used. Those devices are each a continuous rotary type device made up of a cylindrical or polygonal pipe shaped container which is laid horizontally so as to be rotated or swung. In the container, a thermocouple is provided to measure the drying temperature of a material to be dried or the sintering temperature of a material to be sintered. More specifically, in the rotation center portions of both ends of the container or in the rotation center portion of the tail of the container, a steel material is fixedly laid which is long enough to reach the region where the drying or sintering operation is carried out in the container. From the steel material, the thermocouple is suspended, and it is surrounded by the material which is at a temperature measuring position.
The long steel material, from which the thermocouple is suspended, is exposed to a high temperature atmosphere in the drying region or sintering region in the container. While the operation is carried out for a long time, the long steel material is gradually thermally deteriorated, so that its mechanical strength is lowered, and may be bent. If this trouble occurs, the thermocouple is shifted, so that it becomes impossible to measure the temperature of the material at the aimed (intended) part thereof. At worst, the end of the thermocouple is caused to directly contact the inner surface of the container, so that the thermocouple may be broken.
In order to prevent the thermocouple-suspending steel material from breaking, the following method is employed: That is, a necessary number of means are set in the container which are designed as follows: The suspending steel material is inserted in a cylinder which is larger than the former (the suspending steel material). The cylinder is permanently positioned at the rotation center portion of the container with several supporting steel materials which are extended in different directions in the container.
However, the method is disadvantageous in the following points: The thermocouple-suspending steel material, and the supporting cylinder are exposed to the high temperature atmosphere, and the supporting cylinder and the suspending steel member are brought into contact with each other, thus being worn out. That is, it is impossible for the method to stably perform the temperature detection for a long time.